"Her vote is up over last month and Brown has lost support from Democrats," said Darrell West of the Brookings Institution.

"Her convention speech did a good job rallying the base and persuading people that she was on their side. She has put pressure on Brown to explain why he would be a better choice for Massachusetts than she would."

"Democrats for Brown" Not Making a Dent

While the "Democrats for Brown" coalition boasted of its nearly 500 members, most of the Democratic leaders involved have histories of supporting Republican candidates, and the few hundred grassroots supporters are just a fraction of the total number of Democrats enrolled in the Bay State.

"If he's only getting 17 percent and he's gathering less than half of the independent votes, then I think Senator Brown is going to have trouble."

Deeb said Brown needs to appeal to a significant number of Democrats and independent-minded voters with the high Democratic turnout excepted with President Obama on the ballot.

The Political Science professor also opined that if Warren could capitalize on her improved standing among voters and run a positive campaign through to November, she will be in a good position to take the Senate seat.

Jennifer Lawless, director of the Women & Politics Institute at American University, said many people are just starting to pay attention to the race now that Labor Day has passed, and in a state where Democrats outnumber Republicans 3 to 1, the majority are likely to be in Warren's camp.

"Brown has no choice but to push 'Democrats for Brown' and to give people permission to support Obama, but also back him," she said.

"There’s no other way – given district demographics – that he can win."

Warren's Post-Convention Boost

The survey of 756 registered "likely" voters was conducted on September 7, 8 and 9, coming on the heels of the Democratic National Convention in Charlotte, and it represented a five-point gain for Warren since Kimball's last poll on August 21.

"Warren is doing much better among Democrats and Obama voters than she was in the last poll, and Brown's margin among independents has declined," said Robert Boatright, a Political Science professor at Clark University.

"It clearly seems related to the convention, but there's not much of a way to disentangle whether it is generally good feelings among Democrats or response to Warren's speech."

Warren gave a primetime speech at the DNC on Wednesday as the opener for former President Bill Clinton, and new Gallup data shows that Obama is enjoying a three-point boost since his convention appearance on Thursday.

Brown only attended one day of the Republican National Convention in Tampa and avoided much of the national spotlight.

For Boatright, the fact that the poll surveyed "likely" voters, rather than just those registered, was significant.

Obama has performed better among registered voters than among likely voters by a few points. Boatright expects similar results for Warren.

"Although the presidential campaigns won't be doing turnout work here, the Warren campaign of course will. This means we may well see more appeals to younger voters, minorities, and other low-turnout groups."

Still a Long Way to November

Michael Walsh, an attorney and professor of Political Science at Westfield State University, said he was somewhat surprised to see the newest poll results.

While Warren had been slightly ahead of Brown in polls for several months, Brown seemed to be pulling ahead in August, when he recorded a 5-point lead in a Public Policy Polling survey and a 6-point lead in a Kimball report.

"Getting that national attention may have helped her a bit," he said.

"I don't sense a real big shift in the race."

However, there are still a substantial number of undecided voters.

"You'll see the numbers start to harden in the last 21 to 25 days," Walsh said, as those undecideds make up their minds during the final stretch.

Will the "People's Pledge" Hold?

Boatright warned that outside money, which has been largely absent from television ads in the Massachusetts Senate race thanks to both candidates signing the "People's Pledge," may rear its head if the race stays so close with less than two months to go.

"The implosion of the Republican candidate in Missouri means that realistic Republican hopes for a Senate majority must include Brown holding his seat," he said.

"So either the deal on outside spending may collapse in upcoming weeks -- which would have unpredictable polling results -- or expect outside spending on things other than TV."

With the embargo on third-party ads still in place, both Brown and Warren enjoyed favorability ratings of more than 50 percent in the latest Kimball research, fueled at least in part by a bevy of positive ads, including one featuring the Republican Senator shaking hands with President Obama.

"We expect this to be a close race, but what Professor Warren can't change is the fact that she is known for three things: claiming to be the founder of the radical Occupy group, starting the anti-free enterprise 'you didn't build that' movement and for being a fake Indian," said Mass GOP's Tim Buckley.

"Elizabeth Warren is fighting for a level playing field for small businesses and middle-class families, while Scott Brown continues to put the needs of Wall Street, Big Oil, and huge corporations first," said Matt House of the Massachusetts Democratic Party.

"We're going to keep communicating the key differences between these candidates in every corner of the Commonwealth."